I don't know what made it so great but I think the fact it was the first game to truly master the whole 3D concept, it burrowed its way into our brains and will never leave. To this day people still compare modern games to Ocarina of Time, to me this is a testimit of the best game of all time, we are still trying to find a game that's better. It is the bar we set our sights on "If this game is half as good as Ocarina of Time..." this is what i say in my head so often. I personally don't think the a game will be able to beat it until we have the first virtually reality game that truly masters it, like Ocarina of Time did with 3D.